WGU C785 BIOCHEMISTRY UNIT EXAM QUESTIONS
WITH 100% CORRECT AND VERIFIED ANSWERS
100% Correct 67
Incorrect 00
Your answers
1 of 67
Term
Low levels of glutathione are associated with certain types of
ovarian and breast cancers. In the synthesis of glutathione,
glutathione accumulates in the cell, binding to an enzyme in the
pathway and temporarily preventing the synthesis of glutathione.
Which type of inhibition is described by this scenario?
Feedback
Competitive
Allosteric
Uncompetitive
Give this one a try later!
, Increasing the amount of glycine in the diet
One way to increase glutathione levels is to increase the activity of glutathione
synthetase. Glutathione synthetase activity can be increased by increasing the
amount of substrate, or glycine available.
Feedback
The keywords here are that glutathione accumulates and binds to an
enzyme in the pathway to prevent synthesis. Feedback inhibition occurs
when a product of a pathway turns into an inhibitor of an enzyme earlier in
the pathway.
Primary
The primary structure of a protein is the sequence of amino acids held together
by peptide bonds. Peptide bonds are formed by dehydration reactions and
disrupted by hydrolysis.
The first enzyme in the pathway
The final product's structure is more unlike the substrate for the first enzyme in
the pathway than any other, and thus the least likely to fit the active site of
enzyme 1.
Don't know?
2 of 67
Term
What is happening to the pH of the lungs due to exhalation?
CO2 decreases from exhalation, thus the pH of the lungs increases.
CO2 increases from exhalation, thus the pH of the lungs decreases.
,CO2 decreases from exhalation, thus the pH of the lungs decreases.
CO2 increases from exhalation, thus the pH of the lungs increases.
Give this one a try later!
5' - CAG UUA GAU UCA - 3'
The coding DNA and mRNA sequences in transcription will be identical,
except for any T in the coding DNA sequence having a corresponding to U in the
mRNA sequence. The correct answer is 5'-CAG UUA GAU UCA-3'.
CO2 decreases from exhalation, thus the pH of the lungs increases.
The CO2 in the lung decreases as we exhale and the H+ that was on
hemoglobin is recombined with the bicarbonate ion which produces CO2
and H2O. The acidic H+ is now part of water, which is neutral, thus
increasing the pH.
Cooperativity
Cooperative requires the subunits of hemoglobin to work together so they all
release O2 at the same time or are all binding O2 at the same time. Since
myoglobin contains only one subunit, there is no other group to "cooperate"
with. Therefore, cooperativity is a feature demonstrated by hemoglobin and not
myoglobin.
Thymine dimers would accumulate and increase the probability of developing
skin cancer.
A defective nucleotide excision repair pathway would not be able to repair
thymine dimers. The accumulation of thymine dimers would increase the
probability of developing skin cancer.
, Don't know?
3 of 67
Definition
CH3(CH2)4CH = CHCH2CH = CH(CH2)7COOH
In order to answer this question, we need to be comfortable with the
different ways we draw molecular structures. Because fatty acids
are rather simple (boring, almost) molecules that have lots of
carbon (C) and hydrogen atoms (H), it can get really tedious to draw
them all
out in the usual way. To save ourselves the time and trouble of
drawing out all those C's and H's, we simply draw the bonds
between the carbon atoms. This gives us a "zig-zag" structure. We do
not need to draw the hydrogen atoms or the bonds between
them since we know that carbon always makes four bonds to other
atoms. If a carbon is shown making two bonds, for example, with
other carbons (one to the carbon ahead of it in the chain and one to
the carbon behind it), then we know it must be making two other
bonds to other atoms. If we do not show those bonds or atoms, we
agree
that means that those atoms are hydrogen.
First, we indicate the carbon with the three hydrogens as CH3. Then,
the carbon with two hydrogens is written as CH2. Rather than write
out CH2CH2CH2CH2, we simply put parentheses around that group
and the subscript number outside the parentheses tells us that this
occurs 4 times in a row. Next, we come to the carbons in the double
bond, each with one hydrogen. We write this as CH and show the
double bond as =. The next carbon, of course, is also CH. Then we
have another CH2 (but only one, so we don't heed to use
parentheses). Then another double bond CH=CH, and 7 more CH2.
WITH 100% CORRECT AND VERIFIED ANSWERS
100% Correct 67
Incorrect 00
Your answers
1 of 67
Term
Low levels of glutathione are associated with certain types of
ovarian and breast cancers. In the synthesis of glutathione,
glutathione accumulates in the cell, binding to an enzyme in the
pathway and temporarily preventing the synthesis of glutathione.
Which type of inhibition is described by this scenario?
Feedback
Competitive
Allosteric
Uncompetitive
Give this one a try later!
, Increasing the amount of glycine in the diet
One way to increase glutathione levels is to increase the activity of glutathione
synthetase. Glutathione synthetase activity can be increased by increasing the
amount of substrate, or glycine available.
Feedback
The keywords here are that glutathione accumulates and binds to an
enzyme in the pathway to prevent synthesis. Feedback inhibition occurs
when a product of a pathway turns into an inhibitor of an enzyme earlier in
the pathway.
Primary
The primary structure of a protein is the sequence of amino acids held together
by peptide bonds. Peptide bonds are formed by dehydration reactions and
disrupted by hydrolysis.
The first enzyme in the pathway
The final product's structure is more unlike the substrate for the first enzyme in
the pathway than any other, and thus the least likely to fit the active site of
enzyme 1.
Don't know?
2 of 67
Term
What is happening to the pH of the lungs due to exhalation?
CO2 decreases from exhalation, thus the pH of the lungs increases.
CO2 increases from exhalation, thus the pH of the lungs decreases.
,CO2 decreases from exhalation, thus the pH of the lungs decreases.
CO2 increases from exhalation, thus the pH of the lungs increases.
Give this one a try later!
5' - CAG UUA GAU UCA - 3'
The coding DNA and mRNA sequences in transcription will be identical,
except for any T in the coding DNA sequence having a corresponding to U in the
mRNA sequence. The correct answer is 5'-CAG UUA GAU UCA-3'.
CO2 decreases from exhalation, thus the pH of the lungs increases.
The CO2 in the lung decreases as we exhale and the H+ that was on
hemoglobin is recombined with the bicarbonate ion which produces CO2
and H2O. The acidic H+ is now part of water, which is neutral, thus
increasing the pH.
Cooperativity
Cooperative requires the subunits of hemoglobin to work together so they all
release O2 at the same time or are all binding O2 at the same time. Since
myoglobin contains only one subunit, there is no other group to "cooperate"
with. Therefore, cooperativity is a feature demonstrated by hemoglobin and not
myoglobin.
Thymine dimers would accumulate and increase the probability of developing
skin cancer.
A defective nucleotide excision repair pathway would not be able to repair
thymine dimers. The accumulation of thymine dimers would increase the
probability of developing skin cancer.
, Don't know?
3 of 67
Definition
CH3(CH2)4CH = CHCH2CH = CH(CH2)7COOH
In order to answer this question, we need to be comfortable with the
different ways we draw molecular structures. Because fatty acids
are rather simple (boring, almost) molecules that have lots of
carbon (C) and hydrogen atoms (H), it can get really tedious to draw
them all
out in the usual way. To save ourselves the time and trouble of
drawing out all those C's and H's, we simply draw the bonds
between the carbon atoms. This gives us a "zig-zag" structure. We do
not need to draw the hydrogen atoms or the bonds between
them since we know that carbon always makes four bonds to other
atoms. If a carbon is shown making two bonds, for example, with
other carbons (one to the carbon ahead of it in the chain and one to
the carbon behind it), then we know it must be making two other
bonds to other atoms. If we do not show those bonds or atoms, we
agree
that means that those atoms are hydrogen.
First, we indicate the carbon with the three hydrogens as CH3. Then,
the carbon with two hydrogens is written as CH2. Rather than write
out CH2CH2CH2CH2, we simply put parentheses around that group
and the subscript number outside the parentheses tells us that this
occurs 4 times in a row. Next, we come to the carbons in the double
bond, each with one hydrogen. We write this as CH and show the
double bond as =. The next carbon, of course, is also CH. Then we
have another CH2 (but only one, so we don't heed to use
parentheses). Then another double bond CH=CH, and 7 more CH2.
